A complete game a couple of years ago would have left Adam Wainwright’s arm exhausted, or feeling, as he said, like he was “run over by a Mack Truck.” Not this year. After his complete game a week ago against Cleveland, Wainwright’s concern wasn’t the next day -- it was his next start.

That came Saturday in the Cardinals’ 4-2 win over the Cubs. The veteran went 6 1/3 innings in the first game of a seven-inning doubleheader at Wrigley Field, allowing two runs and six hits while striking out six.

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Going into Saturday, Wainwright wanted to use this start to teach the young pitchers something.

“There’s a great lesson here for these youngsters if I go out and pitch a really good game [Saturday] because it shouldn’t be, ‘All right, you pitched a great game, went all nine, so the next couple, shut it down,’” Wainwright said Friday. “That’s not the message I’m trying to portray to these other guys. I want them to expect them to be great every time they go out there. And if they can see an old fellow like me go out there and continue to be good after a start like that, that sets a good example.”

Saturday wasn’t a complete game, and it wasn’t close to a perfect game, but it got the job done, and the Cardinals needed it. Plus, Wainwright is 4-0 for the first time in his 15-year career.

“Is it really?” Wainwright said. “It’s not easy to get big league wins. To quote John Lackey, ‘They don’t give big league wins away on trees.’”

After Ian Happ’s fourth leadoff homer of the year, Wainwright pitched out of trouble in almost every inning -- except when Happ launched his second home run of the game in the fifth inning. In six games against the Cardinals this year, Happ is 7-for-18 with five home runs. In his career against Wainwright, Happ has gone 8-for-14 with four homers.

Take Happ out of the lineup, and Wainwright shut down the Cubs. In the second inning, he loaded the bases with no outs and stranded the runners there with a strikeout, a lineout and a fielder’s choice grounder. In the fourth, Kyle Schwarber hit a leadoff single and made it to third on the next two groundouts, but he was left there as Wainwright struck out Steven Souza Jr. swinging on a curveball.

In the seventh inning, Wainwright got one out before Nico Hoerner singled to bring up Happ -- ending Wainwright’s outing and bringing in closer Giovanny Gallegos, who got out of the jam by getting Happ on a lineout to center and striking out Anthony Rizzo.

“At the end of the day, it comes down to executing pitches,” Wainwright said. “The key is to make good pitches and make those guys hit what you want them to hit.”

The Cardinals were forced to reshuffle their rotation Saturday afternoon when they placed lefty Kwang Hyun Kim on the 10-day injured list after he was hospitalized with a kidney ailment. That moved Dakota Hudson to start Sunday and turned the second game Saturday into a bullpen game, started by Austin Gomber. A taxing series on the pitching staff was something the Cardinals wanted to avoid this weekend against their division rivals with two more doubleheaders this week on Tuesday and Thursday.

But Jack Flaherty only got through 2 2/3 innings in Friday night’s loss, and the news on Kim was another setback.

Long story short: Wainwright needed to cover some innings. That’s what he did, and the Cardinals’ offense backed him up with four runs, two each in the third and fourth innings. They took advantage of the Cubs failing to turn an inning-ending double play for rookie starter Adbert Alzolay, who walked Matt Carpenter with the bases loaded to give the Cardinals a 2-1 lead. They added two more in the fourth on Tommy Edman’s sacrifice fly and Paul DeJong’s single.

“I was locked in on trying to finish today, for me, for the team, but also as the example that that sets,” Wainwright said. “That was my main focus today -- to attack those guys because they put an incredible game on Jack yesterday and worked deep, deep counts. I knew they were going to come out ready to swing on me.”